Validation of PROMIS Physical Function Instruments in Patients with an Orthopaedic Trauma to a Lower Extremity

Nan E. Rothrock*, Aaron J. Kaat, Mark S. Vrahas, Robert V. O'Toole, Sarah K. Buono, Suzanne Morrison, Richard C. Gershon

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


To evaluate the reliability, convergent validity, known-groups validity, and responsiveness of the Patient-Reported Outcomes Measurement Information System (PROMIS) Mobility Computer Adaptive Test (CAT) and PROMIS Physical Function 8a Short Form.Design:Prospective cohort study.Setting:Two Level-I trauma centers.Patients:Eligible adults with an isolated lower extremity trauma injury receiving treatment were approached consecutively (n = 402 consented at time 1, median = 80 days after treatment). After 6 months, 122 (30.3%) completed another assessment.Intervention:Cross-sectional and longitudinal monitoring of patients.Main Outcome Measurements:Floor and ceiling effects, reliability (marginal reliability and Cronbach's alpha), convergent validity, known-groups discriminant validity (weight-bearing status and fracture severity), and responsiveness (Cohen's d effect size) were evaluated for the PROMIS Mobility CAT, PROMIS Physical Function 8a Short Form, and 5 other measures of physical function.Results:PROMIS PFSF8a and Foot and Ankle Ability Measure Activities of Daily Living Index had ceiling effects. Both PROMIS measures demonstrated excellent internal consistency reliability (mean marginal reliability 0.94 and 0.96; Cronbach's alpha = 0.96). Convergent validity was supported by high correlations with other measures of physical function (r = 0.70-0.87). Known-groups validity by weight-bearing status and fracture severity was supported as was responsiveness (Mobility CAT effect size = 0.81; Physical Function Short Form 8a = 0.88).Conclusions:The PROMIS Mobility CAT and Physical Function 8a Short Form demonstrated reliability, convergent and known-groups discriminant validity, and responsiveness in a sample of patients with a lower extremity orthopaedic trauma injury.

Original languageEnglish (US)
Pages (from-to)377-383
Number of pages7
JournalJournal of orthopaedic trauma
Issue number8
StatePublished - Aug 1 2019


  • lower extremity
  • mobility
  • physical function

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine


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